The RD-0124 engine series

With the disintegration of the USSR in 1991, developers of the Soyuz rocket, along with the rest of the nation's space industry, wanted to consolidate its subcontractor network inside the Russian Federation. To accomplish the goal, TsSKB Progress in the city of Samara, developed a new version of its workhorse Soyuz launcher, under research and development plan dubbed Rus. According to the upgrade plan, the Soyuz-2 rocket would sport a brand-new RD-0124 (14D23) closed-cycle engine on its third stage.


Roskosmos head Igor Komarov inspects production line of RD-0124 engine in Voronezh on Feb. 6, 2018.

RD-0124 engine

The 30-ton-thrust RD-0124 engine developed for the Soyuz-2 launcher would have roughly same dimensions (height: 2,327 millimeters, diameter: 1,470 millimeters) and the basic design as the veteran RD-0110 engine on the third stage of the previous Soyuz rockets. The main difference would be the introduction of the so-called closed-cycle system, where oxidizer gas used to drive the engine's pumps, would be then directed into the combustion chamber, where it would burn with the rest of the propellant, rather then being dumped overboard. Such upgrade would increase the performance of the engine and, as the result, the payload of the launcher by some 950 kilograms. A version of RD-0124 was also intended for the Angara rocket.

A special ignition propellant is used to activate the combustion of the engine and pyrotechnic devices used to control the engine's work. Each of four combustion chambers can gimbal along a single axis to steer the vehicle. (145)

RD-0124 engine development

Initial tests firings of the RD-0124 engine reportedly started in 1996 and were completed in February 2004 at KBKhA design bureau in Voronezh. At the time, representatives of the company were quoted as saying that the mass production of the engine could start as early as 2005.

Another test firing (in Voronezh) was conducted on December 27, 2005, clearing the way to full-scale tests of the entire third stage (Block I) of the Soyuz-2-1b rocket at NIIKhimmash facility in Sergiev Posad.

On May 3, 2011, KBKhA announced that "certification" tests of RD-0124 were successfully concluded in Voronezh, declaring the engine operational. By that time, RD-0124 had already flew four missions on the Soyuz-2-1b rocket. The engine accumulated a total burn time of 55,000 seconds in 225 tests, some of which were exceeding the real-life operational conditions of the engine. Another firing, characterized as control and technical testing, took place on Sept. 10, 2011. The head of Roskosmos, Vladimir Popovkin, personally oversaw the test in Voronezh.

RD-0124A for Angara

In April 2012, the RD-0124A engine, intended for the second stage (URM-2) of the Angara family of rockets, underwent climatic tests in a special cold chamber at the KBKhA design bureau in Voronezh in order to certify it for operational conditions at Russian launch sites. Following the climatic tests, the same engine was scheduled to perform three firing tests.

On Dec. 25, 2012, the RD-0124A engine fired for 753 seconds at KBKhA's climatic test chamber in Voronezh to confirm its performance after nine months of climatic tests. Two more tests were still scheduled during 2013, followed by inter-agency certification tests in 2014. The test firing program was to certify the propulsion system for both Soyuz-2.1b and the Angara rocket.

The last tune-up firing of RD-0124A engine was conducted in Voronezh on June 10, 2013, concluding autonomous test program. From the end of June, KBKhA promised to start inter-agency tests of the engine, which would pave the way to the serial production of the engine. Three inter-agency tests of the RD-0124A engine took place from July 16 until Aug. 27, 2013, clearing the way to its use on the Angara rocket beginning in 2014, KBKhA announced on Sept. 3, 2013.

Also in 2013, KBKhA proposed a number of upgrades to the RD-0124A engine, including the introduction of the thrust control nozzles instead of the current gimbal mechanism of the main combustion chamber. The company also proposed to equip the engine with a cutoff system based on a full consumption of any of the propellant components. These upgrades promised to cut the production cost and the mass of the engine, increase the rocket's payload and overall reliability of the propulsion system.


In 2013, KBKhA design bureau conducted the initial development work on a one-chamber replacement for the RD-0124A engine designated RD-0125A. According to the company, the new engine would have a lower mass and a higher thrust and it would be easier to manufacture than its predecessor.

RD-0124MS for the Soyuz-5 launcher


Photo released in April 2021 shows of a combustion chamber for the RD-0124MS engine during a live firing test.

In 2017, NPO Energomash announced a new version of the RD-0124 engine, which was designated RD-0124M and intended for the second stage of the Sunkar/Soyuz-5 project. Despite its name, the new version was radically different from its predecessors, requiring major efforts and time for its development.

By 2019, the engine for the second stage of the Soyuz-5/Irtysh rocket was renamed RD-0124MS and described as two dual-chamber units. For the first time in the Russian practice, the onboard diagnostics system aboard Soyuz-5 was designed to be able to shut down two of four combustion chambers in emergency and continue the flight under the thrust of two remaining chambers of the booster's RD-0124MS engine.

In late February 2021, KBKhA design bureau reported the first test firing of the combustion chamber for the RD-0124MS engine lasting 50 seconds at nominal thrust.

On July 25, 2022, KBKhA announced a successful firing of the RD-0124MS engine as part of tune-up tests. It was the first test using all four chambers of the engine, according to the company. More firings were scheduled by the end of the year before the transition to the live testing of the second stage of the Soyuz-5 rocket, KBKhA said.

On Dec. 20, 2022, KBKhA said that another tune-up firing test was successfully conducted for the first time with full-size nozzles on the engine (unlike previous configurations with shortened nozzles). The company also promised to continue autonomous firings of RD-0124MS in 2023 in parallel with delivery of new engines for ground testing. The same experimental unit was tested again on December 29, this time firing 40 percent longer than the nominal burn prescribed by official Technical Assignment for the launch vehicle. The company said that the ignition and the cutoff of the engine had gone as planned.


Comparison of RD-0110 and RD-0124 engine performance (120):

Thrust in vacuum
298.03 kN
294.3 kN
Specific Impulse
326 seconds
359 seconds
Combustion chamber pressure
6.8 MPa
15.53 MPa
Engine mass
408 kilograms
450 kilograms


This page is maintained by Anatoly Zak

Last update: April 4, 2024

insider content



The four-chamber RD-0110 engine, which was used for several decades on the third stage of the Soyuz family of launchers became the focus of upgrades needed to build the Soyuz-2 launcher. Copyright © 2001 Anatoly Zak


Comparison of the RD-0110 engine from the Soyuz rocket (left) and the RD-0124 engine from Soyuz-2. Click to enlarge. Copyright © 2009 Anatoly Zak


A scale model of the RD-0124 engine, designed to propel upper stages of the Soyuz-2 and Angara rockets. Click to enlarge. Copyright © 2009 Anatoly Zak